What is intrinsic motivation?

I was in therapy at the time and one of the themes that I explored the most was: Where does meaning come from? Where does motivation come from? I think up to that point, I'd been living my life very outside in. I was thinking in terms of the milestones and what does this look like on my CV? And it was a little bit like collecting badges or something. It was a little bit like a game. And then you then pause to think, "Okay, but what about living from the inside out? What would that look like? What motivates me? What's intrinsically meaningful?"